The program expired last week, meaning government checks will stop for those currently eligible for Supplemental Security Income until the program is renewed.

Paul is demanding an investigation into the program after two Iraqi refugees were arrested on terror charges in Kentucky earlier this year.

"They were invited through the refugee program and were on welfare," Paul said of the terror suspects in a statement provided to Roll Call. "This incident alone raises serious questions about the system through which they came to the United States and I am insisting on a full investigation on our practice of providing welfare to refugees."

Democratic aides, however, say the terror suspects arrested in Bowling Green, Ky., did not receive anything from the program addressed by the bill, but instead received cash benefits from a separate, unrelated program for refugees.

Supplemental Security Income goes to a limited group of refugees who are elderly or disabled, including the deaf and the blind. And the bill itself only addresses those refugees who have passed a seven-year deadline to become citizens — a requirement from the welfare reform legislation that passed in the 1990s. Passing the citizenship test is sometimes unrealistic for elderly, deaf or blind refugees, advocates say.

Galen Carey, a vice president of the National Association of Evangelicals, said that Paul's move blocking the aid, which Carey said averages about $670 a month, could send disabled and elderly refugees into homeless shelters.

"It's ironic because these refugees are people who have been victims of terrorism and persecution," he said. "We're just going to leave them on the street? It's not right."

Carey dismissed concerns that there could be disabled or elderly terrorists getting the checks.

"The U.S. refugee resettlement program is one of the most vigorous in the world," he said.

Carey said the refugee program already faced much tighter restrictions after 9/11, and he said the one case in Kentucky is not a good reason to shut down benefits for people receiving them now.

"This bill is not about terrorism, it is about elderly, disabled refugees being able to literally survive," added Kevin Appleby, director of Migration and Refugee Policy for the U.S. Conference of Catholic Bishops. "Our elected officials should know the difference."

The one-year extension of the program would be offset by a $30 fee on diversity visas, with a net reduction in the deficit of $24 million, Democrats said.

Sen. Charles Schumer (D-N.Y.), speaking Monday on the Senate floor when he thought the measure would pass with unanimous consent, noted that President George W. Bush had previously extended the benefits. He also thanked several Republicans for working to help clear the way for the bill, including Sens. Tom Coburn (Okla.), Jeff Sessions (Ala.), John Cornyn (Texas) and Orrin Hatch (Utah).

"Some of the disabled refugees this bill helps are people who have aided American troops overseas in Iraq or Afghanistan — and risked their lives for America's cause," Schumer said. "Others are victims of torture or human trafficking, whose injuries were so severe that they are now unable to sustain themselves without these benefits. ... If we do not act soon, we will cause irreparable harm to these most vulnerable of individuals."

With Paul holding up the bill, it's not clear when or if the Senate might act.

Senate Judiciary Chairman Patrick Leahy (D-Vt.), a backer of the refugee benefits, said Paul's hold shows a larger dysfunction of the institution.

"I would love to see a time when a 100-Member Senate would actually vote on things" and not allow "every one Senator" to force "the whole world ... to revolve around their issues," Leahy said.

Paul has questioned how two Iraqis charged with various terror offenses were allowed into the United States under the refugee program and has sought hearings and an investigation into the program as a result. Paul has said he wants assurances that refugees are properly vetted and questioned how refugees can come from Iraq, given that the country is a U.S. ally.

The refugee bill isn't the only one getting blocked single-handedly by Paul; he is also blocking a bill that would boost safety rules for pipelines that likewise has bipartisan support.

Paul said that bill deserves a full debate and he is concerned that it might not solve problems like the one that led to an explosion in San Bruno, Calif.

"It is a disservice to the families of the victims of the San Bruno pipeline incident to not carefully read this legislation before demanding it be passed without sufficient debate or vote," he said in a statement. "I have serious concerns about whether older pipelines, such as the one at San Bruno, will be grandfathered in and exempt from the regulations presented in this bill. I am meeting tomorrow with experts on this incident from the NTSB and will ask for specific answers on this issue."